Different structures of the brain are involved in processing the pain signal and pain perception. The perception of pain depends not only on the somatic input, but also on individual factors such as ethnic origin, education and socio-cultural environment as well as on psychological factors. The image below displays the main anatomical entities of the brain.

The following structures are of special interest with regard to pain:

  • Cerebral cortex is the part of the brain where the perception as pain takes place.
  • Periaquaeductal grey (PAG; also called the "central grey") is the midbrain grey substance that is located around the cerebral aqueduct. It plays a role in the descending modulation of pain and in defensive behaviour.
  • Thalamus is a symmetrical part of the brain. It constitutes the main part of the diencephalon. The thalamus acts as a relay station disseminating the signals to various areas of the brain, including transmission to the cerebral cortex.
  • Limbic system is a regulation centre, which modulates the pain threshold and emotional reactions.


The brain